I recently bought a bag of Rex Royal flour. If you want to see the spec sheet I've uploaded it http://www.scribd.com/doc/89921328/Rex-Royal-Enr-Mt, it is not on GM's website. On the bag it says not to eat the raw dough or batter. Why is this explicitly said? I have not see this before elsewhere nor in my research since buying the bag. The ingredients appear to be standard and it's not even bromated. Any thoughts?

If a flour is not heat treated or subjected to some other special form of treatment to get rid of pathogens, as is often done with items like eggs and dairy products in doughs, it is possible that someone could get sick (or worse) if the flour used to make the dough or batter is contaminated for any reason. My guess is that GM does not heat treat or otherwise process its flours to get rid of pathogens.

You will often see statements on the packages of frozen pizzas that say that the pizzas should be cooked and not eaten raw. I originally thought that such statements were for alien beings who might have just arrived at our planet but I suspect the reason for the caution is the same as with raw dough or batter.

Peter;Spot on.There is no reasonable way to eliminate possible pathogens from the flour without affecting the protein quality. When used in baby foods, and other sensitive foods, the flour is heat treated which affects the protein's gluten forming quality, but still allows the starch to function as a binder. Most flour is perfectly safe, but there is no kill step taken so it cannot be guaranteed to be safe. This is much like the way we should treat shell eggs. Like we always say, better to be safe than sorry, or dead. Somebody one said that if it wasn't for the oven bakers would have poisoned mankind thousands of years ago.Tom Lehmann/The Dough Doctor

Sourdough starters, like fermented sponges or fermented straight doughs are relatively safe due to their low pH (high acidity). The only cautionary word about starters, especially when developing a new one, is that you really don't know what you have growing in it. Typically, it will be some strain of lactobacillus, but there are no guarantees. While the acidity will protect a mature starter, it is entirely possible to develop aflatoxins from an unwanted fungus, or spore forming bacteria (clostridium) and this is where the potential for problems arises. While this would exist for any bread making process, not just a sourdough. In a sourdough, it is possible for clostridium to produce aflatoxins before the starter becomes sufficiently acidified to control it. Why would you want to taste a raw sour? The proof of the sour is in the flavor it imparts to the baked product.Tom Lehmann/The Dough Doctor

To measure the pH (acidity) of a sour all you need is some Litmus Paper available from your local drug store and a bottle of distilled water. I use a small plastic glass (6-ounce capacity) and put a couple tablespoons of sour into the glass, then I put an equal amount of distilled water into the cup and stir well, let it stand for a minute, then carefully decant (pour) off some of the liquid below into a shot glass, dip the Litmus Paper into the liquid and compare the color to that on the chart provided with the roll of paper to determine the pH. You will want to get paper that will read in the 3.4 to 4.8 pH range.Tom Lehmann/The Dough Doctor